August 28, 2026——The U.S. Food and Drug Administration today approved Mimrylo (rusfertide), a new treatment for adults with polycythemia vera (PV), a rare blood disorder causing excessive red blood cell production. Excess cells thicken the blood, increasing risks of blood clots, stroke, and heart attack.
Mimrylo is the first approved PV therapy that mimics hepcidin, a natural hormone regulating iron in the body. By limiting iron availability for new red blood cell production, it helps control red blood cell levels in patients not adequately managed by existing therapies.
Unmet Need
A key PV treatment goal is maintaining hematocrit (red blood cell proportion) below 45% to reduce cardiovascular risks. This often requires phlebotomy (blood removal). However, some patients require frequent phlebotomies despite standard therapy, creating an ongoing burden.
"Today's approval offers a new, first-in-class option that has the potential to meaningfully reduce patient burden," said Dr. Tanya Wroblewski, Director of the FDA's Division of Nonmalignant Hematology.
Clinical Trial Results
The VERIFY trial evaluated Mimrylo in a multicenter, randomized, double-blind, placebo-controlled Phase 3 study involving 293 adults with PV requiring frequent phlebotomies despite standard care. Patients received Mimrylo or placebo for 32 weeks. Mimrylo was dosed at 19 mg once weekly via subcutaneous injection, titrated to maintain hematocrit below 45%.
The primary efficacy endpoint measured the proportion of patients not requiring phlebotomy between weeks 20 and 32. Overall, 76.9% of Mimrylo patients needed no phlebotomies during the 32-week period, compared to 32.9% on placebo.
Safety
The most common adverse reactions were injection site reactions and anemia.
Regulatory Status
Mimrylo received Priority Review. The approval was granted to Takeda Pharmaceuticals America, Inc.
